This invention relates to the electrodeposition of copper from aqueous acidic plating baths, especially from copper sulfate and fluoroborate baths, and more particularly it relates to the use of certain organic compounds in the baths to give bright, highly ductile, low stress, good leveling copper deposits over a wider range of bath concentration and operating current densities.
In U.S. Pat. No. 3,770,598, assigned to the assignee of the present invention, there has been proposed the addition of certain reaction products to acidic copper plating baths to yield generally the above recited benefits. These prior art additives are formed by the reaction of polyethylenimine with an alkylating agent, such as benzyl chloride. While these reaction products are efficacious in improving the copper deposit, often they may be found to be relatively insoluble in the aqueous acidic plating baths.